A big roast is the very image of a holiday dinner centerpiece. But lately you've probably been finding that the reality doesn't measure up. Too often that roast, so monumental in appearance, is nothing but a giant disappointment. What should be glorious and juicy turns out to be only tough and dry.
The fault isn't with the cook, but the cooked. Beef and pork are now raised to have much less fat than before and that can mean a disappointing dinner. Fortunately, it's a problem that is pretty easily solved by careful preparation, though it may take some retraining on your part.
To unravel this particular puzzle, we searched through hundreds of pages of scientific reports and then cooked about a dozen roasts. We roasted pork and we roasted beef. We cooked them to medium temperatures and rarer. We used ovens that were blazing and hot, or gentle and slow, and some in between -- starting high and finishing low.
What we found surprised us. Looking at the sliced roasts side by side, the differences were astonishing. You might never have guessed that the only thing different about their preparation was the oven temperature. And the secret to the most successful -- a moist, delicious holiday roast -- was a low temperature, for the finished roast and for the oven in which it's cooked.
Don't panic, we're not talking about serving Uncle Bert bloody rare roast beef. When cooked at the lower oven temperature for a slightly longer time, a roast cooked to 125 degrees (normally quite rare) came out looking more like a conservative medium-rare. The meat was firm and definitely cooked through, but still juicy and flavorful.
Meat cooked in a hot oven, on the other hand, was still slightly raw in the center -- even though it had been cooked to the exact same temperature.
To understand how this works, you need to know a little bit about meat and heat. Roasts come from tender cuts of meat -- the muscles that didn't get much exercise. Because they have less connective tissue than other cuts, they can be cooked rarer and in an oven instead of a covered pot -- it's the stringy sinewy cuts that need the long moist cooking of a stew or braise.
Dry cooking -- roasting, grilling and sauteing -- won't make meat more tender, but it does have one distinct advantage over moist. It can brown. The chemical reactions that cause browning in meat don't begin to get going until the temperature on the surface reaches about 300 degrees. Since anything cooked with liquid present will never get hotter than the boiling point -- 212 degrees -- braised meat will never brown. That's why you saute stew meat before you add any liquid. It's also why you should be sure to pat roasts completely dry before putting them in the oven.
It may sound redundant, but with these dry forms of cooking, dryness is always a problem. But it isn't dry air that causes the loss of juiciness, but the effects of the heat. When meat roasts, the protein strands contract and squeeze out the moisture they hold (as we'll see, as much as 25%).
When there is fat in the meat -- either on the outside of the cut or the fine marbling within the muscle -- this isn't such a problem. The fat renders, too, and that makes them seem juicy even if there is less actual moisture in the meat.
And therein lies the rub. Responding to what they perceive as the consumers' demands, the meat industry has been working overtime for the last 20 years to reduce the amount of fat in their products. The percentage of fat in the average piece of pork has been cut by a third since the early 1980s. The percentage of fat in beef fell 27% from the early '80s to 1990 and, according to a beef industry spokesman, is "probably well below that now." In fact, some luxury cuts such as sirloin and tenderloin now meet government standards as "lean," meaning they are low in fat and cholesterol.
This has been done with the intention of making all of us meat eaters leaner as well, and someday it may succeed in that. But a more immediate result has been to reduce the margin of error in roasting. Today if you overcook meat even a little bit, your guests will know it immediately.
We found the key to our roasting puzzle in a scientific paper titled "Effect of Temperature and Method of Cookery on the Retention of Intramuscular Lipid in Beef and Pork" (now, doesn't that make you hungry?). Among the findings was that "higher internal temperature significantly increased shrinkage." What's more, for beef, the leaner cuts lost more weight than the well-marbled ones cooked to the same temperature.
In other words, to keep this new lean meat moist and juicy, you really need to cook it to a lower internal temperature -- rarer -- than you probably did before.
